Curved abrasive fabric



y 3, 1938. R. c. BRYANT 2,115,904

CURVED ABRASIVE .FABRIC Original Filed Oct. 4, 1954 2 Shets-Sheet'l INVENTOR. ROBERT C. BRYANT Q BY MAM/1AM I ATTORNEY.

R. CVBRYANT May 3, 1938.

CURVED ABRASIVE FABRIC Original Filed Oct. 4, 1954 2 Sheets-Sheet 2 INVENTOR ROBERT C- BRYANT BY W4 ATTORNEY.

Patented May 3, 1938 CURVED ABRASIVE FABRIC Robert 0. Bryant, Niagara Falls, N. Y., assignor,

by mesne assignments, to Carborundum Company, Niagara Falls, N. Y., a corporation of Delaware Application October 4, 1934, Serial No. 746,837 Renewed October 4, 1937 Claims.

This invention" relates to the production of curved sheets of abrasive coated fabric and more particularly to theproduction of strips of abrasive coated fabric such as paper and cloth, which 5 are curved longitudinally and transversely.

It has been customary for many years, particularly in the shoe industry, to use curved forms of abrasive coated cloth for various operations. These forms are usually relatively narrow and are furnished in the form of rectangular strips. These strips are curved both transversely and longitudinally and are provided with the proper curvature transversely to make a smooth fit when out to size and arranged about the buffer for which they are intended. For example, for finishing the heels of ladies high heel'shoes it is customary to use a buffer which has a transversely curved peripheral surface aboutwhich is fitted a rectangle of abrasive cloth curved transverselyand 2o longitudinally and known to the trade as a heel and last scouring coil.

In the production of these strips it'has been customary to press flat rectangular strips against a heated roller having a transversely curved pc- 5 rlphery and hold them in such position until the adhesive used in the abrasive cloth softens and until the cloth stretches sufficiently to assume the shape of the periphery of the roll. This may be done by passing a continuous strip part way around the periphery of such a heated rotating roll and pressing the strip against the roll at the place of contact whereby the adhesive softens and the cloth stretches to assume the curved shape of the periphery of the roll. On passing out of con-,

tact with the roll the adhesive sets and assists in retaining the transverse and longitudinal curve so produced in the strip.

This method has numerous disadvantages. The principal disadvantage is that the cloth backing and abrasive layer are stretched longitudinally along the axis of the strip to produce the longitudinal and transverse curvature. This stretch lng breaks the longitudinal threads and otherwise weakens the backing and cracks-and breaks up the adhesive bed carrying the abrasive grains whereby the latter are loosened in their setting and are liableto drop out before having been completely used. The strip is thus weakened at the center where it is likely to receive the most wear anyway, with the result that the strip is worn out prematurely and before the portions adjacent the edges have been completely used.

It has been found also that strips made in this way have a tendency to stretch along the edges in use. This results in a free edge, separated from the buffer surface. Such an edge, on a rapidly rotating buffer, cuts like a knife and presents the danger of injury to the work piece and to the operator.

It is an object of the present invention to provide strips and other forms of abrasive coated fabric which are curved transversely and longitudinally without stretching the backing or the adhesive bed and which will retain their shape in use whereby they fit closely around the buffer or' other form and do not present free edges. Other objects will be apparent from the follow-- ing description and appended claims.

According to the present invention the longitudinal and transverse curvature is produced in a rectangle of abrasive coated fabric by producing parallel inwardly extending corrugations along one or two edges thereof and arranging the corrugations so that they decrease in depth away from the edge at which they start.

The invention will be more particularly described with reference to the accompanying drawings which illustrate certain embodiments of the invention.

In the drawings:

Figure 1 is a plan view of a portion of a strip of flat abrasive coated fabric;

Figure 2 is a plan view of a portion of a strip similar to that shown in Figure 1 but curved transversely and longitudinally by means of inwardly extending corrugations located along the edges of the strip and decreasing in depth away from the'edges to vanishing points between the edges and the longitudinal axis of the strip;

Figure 3 shows a strip similar to that of Figure 2 except that the diagonal corrugations extend across the entire width of the strip, being deepest at the edges and shallowest at the longitudinal axis;

Figure 4 shows a strip similar to that of Figure 2 except that the inwardly extending grooves are perpendicular to the longitudinal axis of the strip;

Figure 5 is a section on A--A of Figure 3;

Figure 6 is a section on B-B of Figure 4;

Figure 7 is a transverse section of a strip similar to Figures 2 and 4 except that the grooves are made shorter along one edge whereby the greatest transverse curvature is adjacent one edge;

Figure 8 shows a strip similar to that of Figure 3 arranged on a form for use;

Figure 9 shows a strip similar to that of Figure 2, arranged on a form for use;

Figure 10 is a view partly in section of a roller for producing corrugations similar to those of Figures 2 and 4 in a strip;

Figure 11 is a similar view of a roller for producing corrugations similar to those of Fig-- tudinal curvature desired;

The corrugations impart to the abrasive surface a resiliency which greatly improves its action in bufling and'scouring operations. When it is desired to produce this resiliency over the entire surface of the strip the corrugations may be extended clear across the strip as in Figure 3 wherein the corrugations 23 extend from one edge to the other, Each corrugation 23 may be of a varying depth throughout its length depending on the extent and degree of curvature desired. For example, if it is desired to produce a transverse curvature substantially a sector of a circle, the corrugations will be deepest along the edges and will decrease in depth to a minimum along the longitudinal axis of the strip as shown in Figure 5. p

The corrugations areordinarily most advantageously arranged diagonally to the longitudinal axis of the strip but the invention is not so limited. In Figure 4 the corrugations 2| are arranged perpendicularly to the longitudinal axis of the strip 22. As in the strips; shown in Figures 2 and 3, the depth, length and frequency of the corrugations 2| will vary depending on the degree and extent of transverse and longitudinal .curvature desired. For example, if it is desired that the transverse curvature be such that the strip is substantially fiat in the central portion and curved toward the edges, the corrugations v 2| may be terminated short of the longitudinal axis of the strip as shown and varied in depth from a maximum at the edges to a minimum at the vanishing point. This is shown in-sectio'n in Figure 6.

If it is desired to produce a transverse curvature of irregular shape, the vanishing points of the corrugations or the points of minimum depth may be arranged at one side or the other of the longitudinal axis, or more or less adjacent an edge thereof, depending on the curvature desired. An example of this construction is shown in section in.Figure 7.

Rectangles may be treated by this method to produce any of the curved shapes demanded by the trade or equivalent shapes. The greatest demand, however, is for curved strips to be cut and formed into heel and last scouring coils and it is with'reference to these strips that'the ,invention is specifically illustrated although it cally at 23' in Figures 8 and9 provided with a coil 24 or 25 fittedabout its periphery and having the ends engaged in slot 26. The coil used in Figure 8 is shown as being made of a strip similar to that illustrated-in Figure 3 wherein the corrugations extend across the strip, while that used in Figure 9ds shown as being made of a strip similar to that illustrated in Figure 2 wherein the corrugations extend inwardly from the edge a distance short of the longitudinal axis.

The corrugations may be produced by any suitable means, but in connection with the present invention it'has been found preferable to use apparatus similar to thatillustrated in Figures 10, 11, and 12, wherein the strip 22 is passed between aproperly grooved roll 21 and a belt 28, which is mounted on roll 21 and pulley 29. The roll 21 may be of steel or other suitable material and provided with a transverse peripheral curvature corresponding to the transverse curvature desired in the finished strip. The roll 21 may approximate the size of the buffer on which the strip is intended for use but should be somewhat smaller in order that the corrugated strip, because of the natural expansion on release from the pressure and by slight expansion of the corrugations, may fit the buffer snugly. The roll should also be provided with transverse grooves 30 and 3| corresponding to the corrugations to be formed in the strip, When making strips having corrugations as shown in Figure 4 or Figure 2, a roll similar to that shown in Figure 10 should be used, wherein the corrugations. or grooves.30 extend only part way across the periphery of the roll, and when making strips having corrugations as shown in Figure 3 a roll similar to that shown in Figure 11 should be used, wherein the grooves 3| extend across'the periphery of the roll.

To press the belt 28 firmly against the strip 22 as it passes around the roll 21, a follower 32 is provided, having a transverse peripheral curvature, the reverse of that of roll 21.

The roll 21 is preferably heated by suitable means, such as an impinging flame, in order to soften the adhesive of the strip to facilitate the conform to the shape of the roll 2'! and which is soft enough to yield under the abrasive grains whereby injury to the abrasive surface or the belt is avoided. The invention is not limited to the arrangement shown in Figure 12 but is capable of other arrangementswherein the strip is passed between a roll and a belt with the abrasive surface adjacent the belt. For example, instead of being arranged about roll 21 and the pulley 29, the belt 28 may be arranged about thefollower 32 and a pulley arranged at the right of the follower 32, power to actuate the apparatus being applied either to roll 21 or follower 32.

The desired curvature'may be applied to the strip by means of inwardly extending corrugations which do not transverse the strip but it is advantageous, in making strips for heel and last scouring coils and for other similar uses, to-extend the corrugations across the strip, making them shallowest at the center or other" place depending on the transverse curve desired. This construction is illustrated in Figures 3, 5, and 8. I

When supported on a base which is not corrugated but of relatively smooth surface, the} corrugated fabric presents a yielding resilient surface because the raised portions of the corrugations are unsupported by the backing. Such surfaces are less exacting in the way of accuracy of registry of the work with the abrasive surface of the device for buffing, scouring or the like. The use of corrugated surfaces results in a softer action on leather and the like, and they do not burn the leather or produce a wavy surface as is the case frequently when ordinary abrasive surfaces are used. When ordinary surfaces are used a nail encountered in the work scores or grooves the abrasive surface which in turn leaves marks on the work. The corrugated resilient surface does not become scored when a nail is encountered and therefore does not produce marks on the work. Strips of this kind have less tendency to shift on the scouring wheel than do the usual linings, make it easier for inexperienced operators to turn out good work, and increase the effective life of the felt covering used on the scouring wheel. v

The advantages of the invention as a means for producing the desired curvature in a strip, or other rectangle, of abrasive fabric, are numerous. Referring to the disadvantages of the previous method of producing such curvature, the present invention permits the production of the necessary curvature without stretching the cloth and cracking the adhesive bed along the longitudinal axis. Strips produced according to the present invention have tight edges when mounted on the scouring or other wheel, and therefore do not form cutting edges to injure the workpiece or operator.

Fabric curved according to this method may be given an excess curvature whereby it is capable of stretching to accommodate itself to a wheel having less curvature. Such stretching involves a straightening of the corrugation and not a stretching of the threads of the cloth. This ability to stretch without breaking or stretching the threads enables the cloth to be handled and adjusted without being permanently deformed from its desired shape.

By means of the invention non-symmetrical shapes such as that shown in Figure 7 may be produced more easily by corrugating the edges only.

The previous method was limited to abrasive coated cloth as paper would not stretch suflicient- -ly, without rupturing, to produce the desired curvature. Since the present invention does not involve stretching the material but only corrugating it, it may be applied'to abrasive coated paper as well as cloth, both included herein, in the term fabric.

I claim:

1. A rectangle of abrasive coated fabric having a pluralityof corrugations extending inwardly from an edge thereof, the depth of thecorrugations being a maximum at the said edge and decreasing away from the edge.

2. A strip of abrasive coated fabric having a plurality of parallel corrugations extending inwardly from an edge thereof to vanishing points short of the axis parallel to the said edge, the depth of the corrugations being a maximum at the said edgeand decreasing away from the edge to the vanishing points.

3. A strip of abrasive coated fabric having a plurality of parallel corrugations extending be tween a pair of opposite edges, the depth of the corrugations being a maximum at an edge and decreasing away from the said edge to a 'mini-. mum between the said pair of opposite edges.

4. A strip of abrasive coated fabric having a plurality of parallel corrugationsextending between a pair of opposite edges, the depth of the corrugations being a maximum at the said edges and decreasing away from the said edges to a minimum at the axis parallel to the said edges.

5. A strip of abrasive coated fabric having a plurality of corrugations extending inwardly from an edge thereof, the depth of the corrugations being a maximum at the said edge and decreasing away from the edge.

ROBERT C. BRYANT. 

